Just curious I was told glass replacement should always be installed from the exterior otherwise it will probably leak....Is this a true statement...I don't understand why it would leak if glass is installed from the interior side.

Imagine that you are on a submarine. If the glass was installed from the inside the pressure of the water would push the glass away from the seal, causing it to leak. For this reason, view portals are installed from the outside, as pressure increases, the glass is forced deeper and harder into the seal, preventing leaks. The same, in effect, happens to windows on a house.

for the same reason we install outswing entry doors as much as possible. im on the coast and were starting to see more and more hurricanes... heavy winds can push on a inswing door which can allow water in very easily.. if its an outswing the wind pushes the door into the weatherstripping creating a even tighter seal